$($a$)$ A horizontal force $|F|=400N$ acts at $A($see Figure $5\mathrm{.}1)$ on the two membered frame. Determine the angle $)(90$ and magnitude of the force, directed along AB$.$ The force acting along $AC$ is given to be $500N$ and the angle $=40($Use Geometric method only without coordinates$)$

$[4$ marks$]$